Electrical connecter plug



Aug. 27, 1935. c.-E. GILBERT 2,012,627

ELECTRICAL CONNECTER PLUG Filed Feb. 28, 1933 10 ATTORW Patented Aug.27, 1935 UNITED STATES PATENT OFFICE ELECTRICAL CONNECTED PLUG CharlesE. Gilbert, New York, N. Y.

Application February 28, 1933, Serial No. 658,955

6 Claims. (01. 173-361) My invention relates to electrical connecterplugs and more particularlyto connecter plugs used in connection withextension cords or conductors for making separable electrical connectionof an electrical appliance with a socket in an electrical circuit.

One of the objects of my invention is to provide an electrical connecterplug so constructed that the insulated wires of an extension cord orconductor may be securely and electrically connected with the connecterblades of the plug without removing the insulation from said wires.

Another object of. the invention is to provide an electrical connecterplug provided with removable connecter blades which may be quickly andeasily secured in place without the use of tools and in such a mannerthat they will firmly secure the ends of an extension cord or conductorto the plug and at the same time make electrical contact with the wiresof said cord.

A further object of the invention is to provide an electrical connecterplug having slots or recesses therein adapted to receive and rigidlysupport a pair of removable connecter blades, said slots being so formedthat when the blades are in position with respect thereto they cannot beaccidentally removed therefrom by reason of any vertical pull exertedthereon.

A further object of the invention is to provide a rugged and eificientelectrical connecter plug construction, made of a few parts which areeasily assembled Without the use of tools, and which is cheap tomanufacture.

Other objects of the invention will be more fully described hereinafterand particularly set forth in the appended claims.

The various features of. the invention are illustrated in theaccompanying drawing in which similar characters of reference are usedto indicate corresponding parts in the several views.

Referring to the drawing:

Figure 1 is a view in front elevation of the electrical connecter plugof my invention;

Fig. 2 is a top plan view of the plug as shown in Fig. 1;

Fig. 3 is a view in side elevation of the plug;

Fig. 4 is an enlarged plan view of the plug with the retaining diskremoved and with one of the connecter blades shown in position;

Fig. 5 is an enlarged sectional view of the plug taken on the line 5-5in Fig. 2, looking in the direction of the arrows;

Fig. 6 is an enlarged sectional view taken on the line 66 in Fig. 2,looking in the direction of the arrows;

Fig. 7 is an enlarged sectional view similar to Fig. 6 but showing thecord or conductor secured to the plug by the connecter blades;

Fig. 8 is an enlarged side elevational view of a modified form ofconnecter blade adaptable for use with an electrical connecter plugconstructed in accordance with my invention;

Fig. 9 is an edge view of the connecter blade shown in Fig. 8;

Fig. 10 is an enlarged side elevational view of another modified form ofcontact blade which is adaptable for use with my improved connecter plugconstruction, the blade being shown in position with respect to the plugwhich is partially indicated in section.

Referring to the drawing in detail, the improved connecter plug of myinvention comprises four parts, namely, a body portion I; two removableconnecter blades 2; and a retaining disk 3.

The body portion of the plug may be made of fibre, bakelite or any othersuitable insulating material and is formed in the same general shape asthat of the usual connecter plug. The external contour of the bodyportion is provided with the depressed grip portions 4 and 5 which areadapted to facilitate the handling of the plug when it is to be insertedin a socket or removed therefrom.

The top or prong end of the body portion is provided with a depressedface 6, forming a peripheral shoulder l. The shoulder I is provided witha rounded edge 8. The depressed face 6 is formed with two rectangularshaped recesses or slots 9 and III which are positioned on either sideof a central aperture I l in said body portion. These recesses or slotsare intended to receive and support therein the removable connecterblades 2. The particular manner in which these slots or recesses areformed is an important feature of my present invention and will be moreparticularly referred to hereinafter.

The depressed face Got the body portion is also formed with a channelportion I2, said channel extends transversely across the body portionand is positioned so that it intersects the central aperture II and therecesses or slots 9 and ID.

The connecter blades 2 are adapted to be removably seated in the slotsor recesses 9 and Ill of the body portion and may be made in severaldifferent shapes. My preferred form of blade is illustrated in Figures 5and 6. Modified forms of blades are shown in Figures 8, 9 and 10.

The preferred form of connecter blade may be made of any suitableconducting material and is formed so that .it is provided with a contactprong end l3 and an enlarged base portion l4 recesses or slots 9 or IIIin the body portion I.

The blade is provided with an elongated slot I5 which extends from thebottom edge of the base to a point near the upper end of the prong 'endportion I3. Said slot forms the blade into two flexible side portions I6and I1. Preferably said slot I5 is enlarged at its upper end to form anaperture I8 for engagement with the usual projection in the contactmember of an electrical outlet.

The slot I5 is slightly offset at the base portion of the connecterblade so as to form a shoulder I 9 in the side portion I6. Said shoulderis pro-- vided with a downwardly projecting edge the purpose of whichwill be referred to later on herein.

The side portion I! of the slotted blade at the base portion thereof isprovided with the serrations or teeth 20. The lower ends of the sideportions I 6 and I1 at their edges adjacent the slot I5 are providedwith the beveled corners 2I and 22. The outer lower corners of the baseportion are also beveled as at 23 and 24.

The base portion I4 of the blade is offset from the contact prong end I3so that it is formed with a shoulder 25 and so that it lies in a planeparallel to said contact prong end. The base portion is also providedwith slits 21 which form in said base the tongue portions 28 and 29.Said tongue portions are bent outwardly from the plane of said base asclearly shown in Figure 6.

The retaining disk 3 is made of a thin piece of flexible insulatingmaterial such as is generally used for similar retaining disks employedfor covering the top of the usual type of plug connecter. The retainingdisk is provided with spaced slots therein and through which theconnecter blades 2 are adapted to extend when said disk is in assembledposition with the body portion of the plug.

The retaining disk 3 is of such size and shape as to make a snug fitover the depressed face 6 or the top of the body portion of the plug andwithin the confines of the shoulder I of said top and so its edge willbe retained. under the rounded edge 8 of said shoulder.

The retaining disk in my improved connecter plug construction serves thedouble purpose of closing the prong end of the body portion and also tohold the connecter blades in proper position with respect to the slotsor recesses 9 and I0.

I will now describe the particular formation of the slots or recesses 9and I0, located in the depressed face 6 of the body portion I. Theserecesses or slots are each formed in a manner which is clearly indicatedin Figure 6. The recess or slot is of a general rectangular shape and ismade of a width throughout its depth which is slightly greater than thethickness of the base portion I4 of the connecter blade so that saidbase portion may be readily inserted in the slot or recess and removedtherefrom. The open end of the slot or recess is made slightly widerthan the lower end of the same so that there is presented an inclinedside portion 30 which extends from the opening of the slot toapproximately the lower or closed end thereof. The other side of theslot is provided with an inclined portion 3I which extends upwardly fromthe lower part of the slot and terminates at its upper end-in a lip orprojecting edge 32.

The length of the slot or recess throughout its depth is made slightlyless than the normal length of the slotted connecter blade at its basewhich is adapted to be seated in either of the portion I4 so that it isnecessary to compress the side portions I6 and I1 inwardly when the saidbase is to be positioned in said slot or recess.

In depth, the slot or recess is made substantially equal to the heightof the base portion I4 of the connecter blade 2.

When it is desired to assemble the connecter plug for use in connectionwith an electric cord or conductor, the cord or conductor is firstpassed through. the central aperture II of the body portion of the plugand the woven covering therefor is slipped back so as to expose the endsof the two insulated wires. The end of one of the insulated wires isinserted in the slot I5 at the base portion I4 of one of the connecterblades, the insertion of the wire being facilitated by reason of thebeveled corners 2I and 22 at the bottom edge of the side portions of thebase. When the end of the wire is thus positioned in said slot I5, theteeth or serrations 24 formed on the edge of the side portion H of theblade will engage in the insulation surrounding said wire. The insertionof the insulated wire in the slot of the blade will cause the sideportions I6 and ll of the base to be spread slightly away from eachother and due to the spring or resiliency of said side portions, thewire will be held securely in the slot and the serration or teeth 24will be caused to pierce the insulation around said wire. The shoulderI9 formed in the base by the offsetting of the slot I5, will prevent theinsulated wire from being forced into the upper portion of the blade anddue to the pointed formation thereof it will also tend to grip andpierce the insulation over the wire.

The other insulated wire of the cord or conductor is connected to theother connecter blade of the plug assembly in a similar manner.

The insulated wires of the cord or conductor are inserted in the slotsof the connecter blades so that-the end portion of the same will extendbeyond the plane of base.

The connecter blades 2 with the conductor wires connected thereto arethen inserted in their respective slots or recesses 9 and III suchoperation being facilitated by reason of the beveled corners 23 and 24formed on the base cue of the blade.

By reason of the fact that the length of the recess or slot is slightlyless than the normal length of the slotted base portion I I of theblade, it is necessary that the side portions I6 and I! of the blade becompressed against the insulated wire in order that the base will fit inthe slots. When this is done the serrations or teeth 20 will be causedto bite completely through the insulation and make electrical contactwith the wires, and as the base of the blade is forced into the slots inthe body portion of the plug, the wire will be firmly gripped and heldby the blade in said slot or recess.

The connecter blades when being inserted in their respective recesses orslots 9 and III are held in a tilted position as indicated in Figure 6and so that the projecting tongues 28 and 29 of the base portion aredirected toward the side of the slots that is formed with the projectingedge or lip 32. When the base of the blade has been completely insertedin its slots or recess in the body portion it will assume an uprightposition as illustrated in Figure 6 and the projecting tongues 28 and 29will become engaged under the projecting edge or lip 32 of the slot andsaid blade will become locked in said slot or recess of the base againstany vertical or upward pull.

The blade may be inserted into the slot in the tilted manner abovedescribed by reason of the enlargedopening of the slot and the inclinedside 30. When the blades 3 are in position in the slots or recesses inthe body portion, the sides of the bent out tongue portions of the baserest against the inclined side portion 3i of the said slot formation.

The insulated wires of the conductor when forced into the slots orrecesses 3 and ID by the connecter blades 2 will be further clampedagainst the upper edges of the slot or recesses and the ends of saidwires and the portions thereof protruding through the central apertureII will lie in the channel l2 formed in the recessed face of the bodyportion of the plug.

To complete the assembly of the connecter plug the retaining disk 3 isslipped over the prong ends of the connecter blades and is snapped intoposition under the rounded edge 3 of the peripheral shoulder 1 formed inthe body portion. The holes in said disk 3 through which the prong endof the connecter blade projects are so positioned that when the disk isin place with respect to the body portion of the plug, said disk willrigidly hold and prevent the connecter blades from being moved laterallyin the slot so as to disengage the projecting tongues 23 and 23fromunder the projecting lips 32 of said slots or recesses 3 and Hi.

In disassembling the plug all that is necessary is to remove theinsulating disk 3 from out of engagement with the edge 8 of the shoulderI and liftv it from the body portion of the plug. The blades are thenrocked towards the inclined side 30 of the slot or recess in the bodyportion so that the tongues 23 and 23 become disengaged from under theprojection or lip 32 and the blade is then lifted out of said slot orrecess and the wire removed from the slots in said blades.

In Figure 8 I have shown a modified form of blade which may be used witha plug body portion constructed as above described. With this type ofconnecter blade the insulated wireis forced into the slots or recessesof the body portion of the plug by the blade which is made of a solidpiece of conducting material 33. The base portion of this type of bladeis formed with the slits 34 and 35 forming tongue portions 33, 31. Saidtongues are bent outwardly from the base as c early shown in Figure 9.The lower edge of the base portion is formed with the serrations orteeth 33. The base portion of the blade is offset from the prong portionin the same man-- ner as the blade previously described and so as toform the shoulder 39.

In the use of this type of connecter blade the serrations or teeth 38bite into the insulation of the wire as it is forced into the slot orrecess of the base portions and thus makes the desired electricalcontact with the wire. The blade is inserted and becomes locked in theslot or recess in the same manner as in the case of the blade previouslyreferred to.

In Figure 10 a further modified form of blades is shown. This blade ismade of a solid piece (if conducting material 40. The base portion ofthe blade is provided with the slits 4| and 42 which form the tongues 43and 44. Said tongues are bent outwardly from the plane of the base inthe same manner as the tongues formed in the previously describedblades. The base portion of this type of blade is also offset from theplane of the prong portion thus forming a shoulder 45. The lower lefthand corner of the base is formed with a square shaped cut out ornotched portion therein having the serration or teeth 43 provided along'one of the sides of said notched portion.

This construction of blade is forced inthe slot or recess of the bodyportion so that the insulated wire is positioned in the cut out ornotched portion thereof. As the wire is forced into the slot or recess,the wire is forced against the sides of the slot and the serrations orteeth 43 bite into the insulation and cause the blade to make electricalcontact with the wire.

From the foregoing it will be seen that I have provided an exceedinglysimple and eificient construction for an electrical connecter plug whichis made of a few simple parts which are cheap to manufacture and whichmay be assembled quickly and without the use of tools. when the partsare in assembled relation it presents a ruggedly constructed connecterplug which will not get out of order and which will withstand unusualstrains that may be placed on the cord or conducter wires connectedthereto.

It will be understood, of course, that the term "plug" as used in thespecification and claims is not limited to forms having the generalappearance of those shown in the drawing but includes any other formshaving the characteristics described and claimed, irrespective ofsuperficial appearance.

What is claimed is,

1. An electric plug comprising a body portion provided with a recessopen at one end for receiving and supporting therein a contact blade, atcontact blade removably seated in said recess and provided with means topierce the insulation of an insulated wire and to make contact with thewire within when said blade is seated in said re.- cess, means formed insaid recess engaging with the contact blade to retain the same in wirecontacting position against longitudinal displacement, and means formaintaining said contact blade in locked engagement with said retainingmeans of said recess against lateral displace-' ment.

2. An electric plug comprising a body provided with a longitudinalrecess, a contact blade re-' movably seated within said recess andhaving an offset upwardly extending tongue, a shoulder on the wall ofsaid recess the under side of which engages with said tongue to retainsaid contact blade against longitudinal displacement, means on saidcontact blade for piercing the insulation of an insulated wire andmaking contact with the wire within, and means for retaining saidcontact blade against lateral displacement.

3. An electric plug comprising a body provided with a longitudinalrecess for the reception of an insulated wire and a contact blade, aremovable contact blade one end of which is seated within said recess,said end terminating in means for piercing the insulation of aninsulated wire and making contact with the wire within, means formaintaining said blade in said recess in wire contacting positionagainst longitudinal displacement, and means for retaining said bladeagainst lateral displacement.

4. An electric plug comprising a body having a recess for the receipt ofan insulated wire and a contact blade, a removable contact blade one endof which is seated within said recess, said end terminating in means forpiercing the insulation of an insulated wire and making contact with thewire within, an oifset tongue on said blade, a shoulder on the wall ofsaid recess engaging with said tongue to maintain said blade in wirecontacting position and against longitudinal displacement, and means formaintaining said blade against lateral displacement.

5. An electric plug comprising a body having a' recess within it open atone end, a removable contact blade seated within said recess and havingan offset end provided with means for piercing the insulation of aninsulated wire and making contact with the wire within, means on said 10blade engaging with cooperating means in' said recess to maintain saidblade against longitudinal displacement, and separate means formaintaining said blade against lateral displacement;

